Methods of Making Molybdenium Titanium Sputtering Plates and Targets

ABSTRACT

Molybdenum titanium sputter targets are provided. In one aspect, the targets are substantially free of the β(Ti, Mo) alloy phase. In another aspect, the targets are substantially comprised of single phase β(Ti, Mo) alloy. In both aspects, particulate emission during sputtering is reduced. Methods of preparing the targets, methods of bonding targets together to produce large area sputter targets, and films produced by the targets, are also provided.

FIELD OF THE INVENTION

This invention relates to molybdenum-titanium sputter targets having lowparticulate emissions. The targets can be bonded together to make alarge area targets useful in the production of certain types of thinfilms, such as those used to make flat panel displays such as thin filmtransistor-liquid crystal displays (TFT-LCDs).

BACKGROUND INFORMATION

Sputtering is a technique used to produce a metallic layer in variousmanufacturing processes used in the semiconductor and the photoelectricindustries. The properties of films formed during sputtering are relatedto the properties of the sputtering target itself, such as the size ofthe respective crystal grain and the formation of secondary phase withdistribution characteristics. It is desirable to produce a sputtertarget that will provide film uniformity, minimal particle generationduring sputtering, and the desired electrical properties.

Various sputtering techniques are used in order to effect the depositionof a film over the surface of a substrate. Deposited metal films, suchas metal films on a flat panel display device, can be formed by amagnetron sputtering apparatus or other sputtering techniques. Themagnetron sputtering apparatus induces plasma ions of a gas to bombard atarget, causing surface atoms of the target material to be ejected anddeposited as a film or layer on the surface of a substrate.Conventionally, a sputtering source in the form of a planar disc orrectangle is used as the target, and ejected atoms travel along aline-of-sight trajectory to deposit on top of a wafer whose depositionface is parallel to the erosion face of the target. Tubular-shapedsputtering targets can also be used, as described in co-pendingapplication Ser. No. 10/931,203.

Sputtering targets may be desired which comprise materials orcombinations of materials that cannot be made by conventional means suchas rolling. In such cases, targets are made by hot isostatic pressing(HIP) powders. Ideally, the target is made in a single step. However,physical limitations of powder packing density and size of HIP equipmentmake it necessary to join smaller segments in order to produce largesputtering targets. For single-phase targets, conventional processingsuch as welding may be used; for multi-phase materials or where alloyformation is to be avoided for any reason, solid-state edge to edgebonding is preferred.

Interconnects in semiconductors and TFT-LCDs are evolving from aluminumand toward copper, thus new diffusion barriers are needed. Titaniumprovides excellent adhesion properties while the molybdenum contributesits dense barrier stability. Integrated circuits (for semiconductors andflat panel displays) use Mo—Ti as an underlayer or capping layer foraluminum, copper, and aluminum alloys to minimize hillocks formation, tocontrol the reflectivity and provide protection from chemical attackduring photolithography.

U.S. Pat. No. 5,234,487 describes methods of producing tungsten-titaniumsputter targets with little or no β(Ti, W) alloy phase. U.S. Pat. No.5,896,553 describes a titanium-tungsten sputter target which issubstantially all single phase β(Ti, W). Neither patent discloses theuse of other materials as substitutes for tungsten.

U.S. Patent Application Publication 20050189401 discloses a method ofmaking a large Mo billet or bar for a sputtering target wherein two ormore bodies comprising Mo are placed adjacent one another (e.g. stackedone on the other) with Mo powder metal present at gaps or joints betweenthe adjacent bodies. The adjacent bodies are hot isostatically pressedto form a diffusion bond at each of the metal-to-Mo powderlayer-to-metal joint between adjacent bodies to form a billet or barthat can be machined or otherwise formed to provide a large sputteringtarget. This patent publication discloses bonding of major sidesurfaces, not edge-to-edge bonding of plates.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a method for preparing amolybdenum-titanium sputtering target having substantially no β(Ti, Mo)phase present, the method comprising the steps of:

(a) providing powders of molybdenum and titanium wherein said titaniumpowder is present in an amount of about 5-95 atomic %, based on thetotal atomic % of the molybdenum and titanium powders, the balance beingmolybdenum powder;

(b) blending the molybdenum and titanium powders to produce a blendedpowder;

(c) optionally, consolidating the blended powder;

(d) encapsulating the consolidated powder; and

(e) compacting while heating the encapsulated powder to produce a firstMoTi target plate.

The method can further comprise the steps of:

(f) removing a portion of the encapsulation on the first target plate;

(g) bonding the first target plate to a second MoTi target plate alongan edge of the first and second plates to produce bonded plates; and

(h) compacting while heating the bonded plates to produce a bondedtarget plate. The bonded target plate is at least 55 inches by 67 inchesin area.

In an additional aspect, the present invention provides a method ofpreparing a molybdenum-titanium sputtering target having a singleβ(Ti,Mo) phase, the method comprising the steps of:

(a) providing powders of molybdenum and titanium wherein said titaniumpowder is present in an amount of about 5-95 atomic %, based on thetotal atomic % of the molybdenum and titanium powders, the balance beingmolybdenum powder;

(b) blending the molybdenum and titanium powders to produce a blendedpowder;

(c) optionally, consolidating the blended powder;

(d) encapsulating the consolidated powder; and

(e) compacting while heating the encapsulated powder to produce a MoTitarget plate having a single β(MoTi) phase.

In yet another aspect, the present invention provides a method ofbonding two or more sputter target plates together to produce a largearea sputter target, the method comprising:

(a) cleaning an edge of each of the two or more target plates;

(b) optionally, providing a bonding material on an edge of at least oneof the two or more target plates to be bonded;

(c) encapsulating the two or more target plates; and

(d) compacting while heating the two or more target plates to produce alarge area sputter target plate,

wherein the large area sputter target plate is at least 55 inches by 67inches in area.

The present invention also provides a molybdenum-titanium sputteringtarget having an area of at least 55 inches by 67 inches.

In additional aspects the present invention further provides amolybdenum-titanium sputtering target having substantially no β(Mo, Ti)alloy phase; and a molybdenum-titanium sputtering target having a singleβ(Mo, Ti) alloy phase. These and other aspects of the present inventionwill become more readily apparent from the following figures, detaileddescription and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further illustrated by the following drawings in which:

FIGS. 1A and 1B are phase diagrams of molybdenum-titanium alloyformation.

FIG. 2A is an SEM micrograph of a sample subjected to HIP for 4 hours at690° C., 15,000 psi.

FIG. 2B is an SEM micrograph of a sample subjected to HIP for 4 hours at825° C., 15,000 psi.

FIG. 2C is an SEM micrograph of a sample subjected to HIP for 4 hours at925° C., 15,000 psi.

FIG. 2D is an SEM micrograph of a sample subjected to HIP for 4 hours at1038° C., 15,000 psi.

FIG. 3A is an SEM micrograph of a sample subjected to HIP for 8 hours at725° C., 15,000 psi.

FIG. 3B is an SEM micrograph of a sample subjected to HIP for 8 hours at750° C., 15,000 psi.

FIG. 3C is an SEM micrograph of a sample subjected to HIP for 8 hours at780° C., 15,000 psi.

FIG. 3D is an SEM micrograph of a sample subjected to HIP for 4 hours at750° C., 15,000 psi.

FIG. 4A is an SEM micrograph of a sample subjected to HIP for 4 hours at750° C., 15,000 psi.

FIG. 4B is an SEM micrograph of a sample subjected to Re-HIP for 4 hoursat 825° C., 15,000 psi.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about”, even if the term does notexpressly appear. Also, any numerical range recited herein is intendedto include all sub-ranges subsumed therein.

In one aspect of the present invention, a sputtering target of Mo and Tiis made having substantially zero Mo—Ti alloy phase. As used herein,“substantially zero” means from about 15% (by volume) or less β(Ti, Mo).Mo—Ti targets in accordance with the invention preferably comprise fromtrace to 12% by volume of undesirable β(Ti, Mo), most preferably fromtrace to 10% by volume β(Ti, Mo), as determined by SEM-EDS analysis.Another method of determining alloy formation is by X-ray diffractiontechniques. These targets have a density of about 95% of the theoreticaldensity or greater.

In another aspect of the present invention, a sputtering target of Moand Ti is made having substantially all single phase β(Ti, Mo) alloy.SEM-EDS analysis of the microstructure of a target is used to determineif the target microstructure consists of multiple phases of Mo and Ti,or if a single β(Mo, Ti) phase is formed.

The phase diagram for Mo—Ti shown in FIG. 4 and taken from Massalski,Binary Alloy Phase Diagrams Vol. 2, Ed. T. B. Massalski, ASMInternational, Metals Park, Ohio, pp. 1640, indicates that in order toavoid formation of the β(Ti, Mo) phase during processing of Mo—Ti alloysthe processing temperature should be equal or below the monotectoidtemperature of 695°±20° C. Accordingly, one method of reducing theformation of β(Ti, Mo) in a sputter target is to manufacture and use thepart in a manner that prevents the target temperature from exceedingthis monotectoid temperature. In practice, the temperature of formingthe target will be slightly higher because slightly higher temperaturesprovide better consolidation.

Alternatively, and as indicated in the phase diagram, use oftemperatures above 695° C., under equilibrium conditions, will result insingle phase alloy formation.

The amounts of titanium and molybdenum will vary depending on thedesired properties of the film to be produced from the sputteringtarget. Typically, titanium powder will be present in an amount of about5-95 atomic %, based on the total atomic % of the molybdenum andtitanium powders, the balance being molybdenum powder. For someapplications, the powder will comprise 40-60 atomic % titanium, with thebalance molybdenum; for others the powder will comprise 50 atomic %titanium and 50 atomic % molybdenum.

The particle sizes of the molybdenum and titanium powders may be variedin accordance with the principles of the present invention. When atarget having substantially zero alloy phase is desired, the preferredaverage particle size of the molybdenum powder is in the range of 2 to150 microns, more preferably 10-30 microns. The average particle size ofthe titanium powder is in the range of 40 to 150 microns, morepreferably 40-60 microns. Both the molybdenum and titanium should behigh purity powders, with both the molybdenum and titanium powdershaving at least 99.5% purity.

When a single alloy phase target is desired, smaller particle sizes areused. The average particle size for the molybdenum powder is preferablybetween 0.1-25 microns, more preferably less than 5 microns. For thetitanium powder, the desired average particle size is preferably 5-50microns, more preferably 25-35 microns.

The molybdenum and titanium powders are blended in accordance withpowder blending techniques that are well known in the art. For example,mixing may occur by placing the molybdenum and titanium powders in a drycontainer and rotating the container about its central axis. Mixing iscontinued for a period of time sufficient to result in a completelyblended and uniformly distributed powder. A ball mill or similarapparatus may also be used to accomplish the blending step. Theinvention is not limited to any particular mixing technique, and othermixing techniques may be chosen if they will sufficiently blend themolybdenum and titanium starting powders.

The blended powder is optionally then consolidated in a preliminarycompacting step to a density which is from 60-85% of theoreticaldensity. The consolidation can be accomplished by any means known to oneskilled in the art of powder metallurgy, such as by cold isostaticpressing, rolling or die compaction. The length of time and amount ofpressure used will vary depending on the degree of consolidation desiredto be achieved in this step For some types of targets, such as tubular,this step may not be necessary.

Following the preliminary consolidation step the consolidated powder isencapsulated, such as in a mild steel can. Encapsulation can also beaccomplished by any method that will provide a compact workpiece that isfree of an interconnected surface porosity, such as by sintering,thermal spraying, and the like. As used herein, the term “encapsulation”will refer to any method known to one skilled in the art for providingthe compact piece free of interconnected surface porosity. A preferredmethod of encapsulation is by use of the steel can.

After encapsulation the encapsulated piece is compacted under heat andpressure. Various compacting methods are known in the art, including,but not limited to, methods such as inert gas uniaxial hot pressing,vacuum hot pressing, and hot isostatic pressing, and rapidomnidirectional compaction, the Ceracon™ process. Preferably, theencapsulated piece is hot isostatically pressed into the desired targetshape, as that method is known in the art, under pressure of 75-300 MPa,more preferably 100-175 MPa, at temperatures of 725°-925° C., morepreferably 750°-850° C., for a period of 2-16 hours, more preferably 4-8hours. Other methods of hot pressing can be used to produce the Mo—Tisputtering targets of the present invention, so long as the appropriatetemperature, pressure and time conditions are maintained.

After the final compaction step the target plate can be machined to thedesired size and shape, and optionally bonded to a backing plate, as isknown in the art, to produce the final sputtering target.

Finished sputter targets of the present invention have a density ofgreater than about 90% theoretical density and preferably at least 95%of theoretical density.

When a larger sputter target is desired, two or more target plates ofthe present invention can be bonded together in an edge-to-edge fashion.In other embodiments, the bonding method described below can be used tobond target plates made from other materials to make a larger sputteringtarget. Such materials include, but are not limited to, Ti—W, Zr—Mo,Al—Nd, Nb—Mo, Al—Si, Ni—Ti, Fe—Ti, Fe—Tb, Al—Zr, Nb—Ti, and otheraluminum, chromium, niobium, zirconium, iron, and tantalum alloys, andthe like. Other bonding materials will be used, depending on thecomposition of the materials in the target.

When bonding target plates having substantially zero β(Ti, Mo) alloyphase, bonding is desired to be accomplished while still maintainingdiscrete elemental phases and without a great increase in the amount ofthe alloy, in this case, MoTi. Thus, conditions for bonding should be ata temperature high enough to affect bonding but not so high as topromote alloy formation. The type of bond medium is also a factor incontrolling alloy formation. In the case of the Mo—Ti system, possiblebond materials include titanium powder, titanium sheet, foil, foam,expanded metal, combined titanium and molybdenum powders or molybdenumpowder or combinations of these. It is also possible to weld two or moreplates together, as welding methods are known in the art.

The bonding method of the present invention may have applicability insystems unrelated to sputtering where the presence of brittle or lowstrength phases, e.g., order intermetallics or Laves phases, would makerolling or welding problematic. For example, titanium forms many suchphases when combined with Fe, Ni and Co.

In the bonding method of the present invention, the edges of plates orsegments to be joined are machined and cleaned to present suitablesurfaces for bonding. Typically, the target plate is a slab between ½and 36 inches in thickness, and therefore the surface to be bonded is nomore than 36 inches thick. More typically, the surface to be bonded isbetween 4 and 8 inches thick. If the bonding material is other thanpowder, cleaning is done by a method that leaves no residue. Bonding isaccomplished by placing the bonding material between the machinedsurfaces, and placing the assembly in a container, such as a mild steelcan, that is capable of being hermetically sealed and of a constructionthat is capable of withstanding the temperatures and pressuresencountered in a vacuum pump. The container and assembly may be heatedto assist in removal of gases and moisture. The container is thenhermetically sealed and placed in a HIP vessel for consolidation.

Consolidation is accomplished using pressures and temperatures asdescribed above, 75-300 MPa, more preferably 100-175 MPa, attemperatures of 700°-950° C., more preferably 750°-850° C., for a periodof 2-16 hours, more preferably 4-8 hours. Following HIP, the containeris removed by mechanical means or by acid digestion.

The large area plates of the present invention will preferably be atleast 55 inches (1400 mm) by 67 inches (1700 mm), sometimes at least 60inches by at least 95 inches.

EXAMPLES

The following examples are intended to illustrate the invention andshould not be construed as limiting the invention in any way.

Example 1 Preparation of Target

In order to select HIP conditions, sub-sized specimens were made byVendor A and Vendor B. Vendor A's specimens finished at a diameter ofabout 0.5-in by 5-in. long. Vendor B's specimens were about 2-in. indiameter by 3-in. long.

Powder Blending

Titanium powder (Grade Ti-050, 100/325 mesh from Micron Metals) andmolybdenum powder (MMP-7, −100 mesh, from H. C. Starck) were blended ina V-blender in proportions to achieve 33.3% Ti (by weight). Blendingtime was adjusted to achieve uniform distribution. No protectiveatmosphere was used during blending or discharging of the blenders.

CIP

Blended powders at Vendor A were Cold Isostatically Pressed (CIP) at19,000 psi to approximately 60% theoretical density (about 4.3 g/cc).The Vendor B specimens were CIP'd at 30,000 psi and achieved densitiesfrom 64% to 70% of theoretical (4.6 to 5 g/cc).

Encapsulate, Out-Gas & Hip

CIP'd compacts were placed into steel cans (C1018, drawn-over-mandrelseamless tubing, ⅛″ wall) with a Mo-foil barrier between the compact andthe can wall. The canned compacts were heated to approximately 200° C.under dynamic vacuum until they could achieve an internal pressure of10μ and a leak-up rate of no more than 100 μ/min. Cans were then sealedby means known in the art using a process comprising crimping, cuttingand fusing the cut end of their evacuation tubes.

Out-gassed and sealed can assemblies were Hot Isostatically Pressed(HIP) for four hours at 15,000 psi at various temperatures. Vendor Aused 680°, 750°, 825°, 950° and 1038° C.; Vendor B used 690°, 825°, 925°and 1040° C.

Results

Samples were cut from each of the test billets and evaluated fordensity, microstructure by metallographic examination and SEM-EDS, andhardness. Density results are summarized in Table 1. Densities, asmeasured by the Archimedes method, from Vendor B followed predictedbehavior; however, densities of samples HIP'd at Vendor A were lowerthan expected and showed non-uniform deformation.

TABLE 1 Densities in g/cc after HIP for 4 hours at 15,000 psi 680° 690°750° 825° 925° 950° 1038° 1040° C. C. C. C. C. C. C. C. Vendor 6.73 7.147.22 7.27 B Vendor 6.2 6.5 6.52 6.99 7.10 A

Metallographic examination revealed the microstructure to be Moparticles embedded in a titanium matrix. Surrounding the Ti particles isan alloy phase of Mo dissolved in Ti. FIGS. 2A-2D show examples of theprogression of increasing alloy phase with HIP temperature. Phaseanalysis of the samples to determine composition of the alloy was doneusing Energy Dispersive Spectroscopy on a Scanning Electron Microscope(SEM-EDS). The images, taken in the secondary electron mode, highlightthe atomic number contrast. Titanium appears darkest, molybdenum appearslightest and the gray of the alloy phase is between the two. Althoughnot readily detectable in these images, a compositional gradient existsin the alloy phase, with the highest Mo content found bordering thepatches of Mo, and the lowest Mo is found adjacent to the Ti patches.The lightest gray phase in molybdenum. The sample from 690° C. showsonly Mo and Ti. At 825° C., there is a third phase present. The lightestgray is Mo, the darkest gray is Ti, and surrounding the Ti is an alloyphase that contains 10% to 20% Mo, by weight. At 925° C., very littlepure Ti remains, and at 1038° C. the microstructure comprises Mo and analloy of Ti with about 25% Mo by weight.

Microstructure and density vs. HIP temperature indicated that theoptimum temperature for the first HIP may be in the range of 720° C. to780° C. Three additional runs were made at 725°, 750° and 780° C., allfor eight hours at 15,000 psi. These were evaluated for density,microstructure, hardness and alloy phase composition. Results of thosetests show an improvement in densification over that predicted from theplot of density and temperature for the four-hour runs made previously.SEM photo-micrographs for these runs are shown in FIGS. 3A-3D. Forcomparison, HIP for four hours at 750° C. and 15,000 psi resulted in adensity of 7.07 g/cc.

TABLE 2 Densification response at 15,000 psi for 8 hours HIP temperature725° C. 750° C. 780° C. Density (g/cc) 7.05 7.11 7.14

Concurrently, a large block of MoTi was CIP'd at 19,000 psi by Vendor Ato 6.8″ by 6¾″ by 17¼″ and about 65% dense (4.78 g/cc) and HIP'd forfour hours at 15,000 psi and 750° C. to finish at a size ofapproximately 5¾″ by 5½″ by 15½″ (5.697″×5.425″×15.406″ at its smallestdimensions).

Producing monolithic targets with dimensions in excess of 1550 mm frompowder is beyond the current equipment capability and requires joiningsegments. Joining may be accomplished by a second HIP operation;however, conditions must be carefully selected to avoid the formation ofthe alloy phase. Following HIP at 750° C. for four hours at 15,000 psi,samples were re-HIPed at 8250 for four hours at 15,000 psi. FIGS. 4A-4Bshows typical microstructure resulting from the additional HIP cycle.The relative proportion of the MoTi alloy phase has increased in thesample from 825° C. over that of the 750° C. sample, but the re-HIP'dmicrostructure is qualitatively similar to that of the 825° C. sample inFIG. 2. Density has increased to 7.20 to 7.22 g/cc in the samplere-HIP'd at 825° C. as compared to the density after a single HIP cycleat 825° C., 4 hours, 15,000 psi (7.14 g/cc).

Example 2 Bonding

Blended Mo and Ti powders at a ratio of 50 atomic percent each were coldisostatically pressed to approximately 65% to 75% theoretical density toform a block approximately 6-in. by 6-in. by 20-in. and encapsulated ina steel can using methods known in the art. The powder-filled can washot isostatically pressed for four hours at 15,000 psi and 750° C. Theconsolidated compact was removed from the steel can and cut into slicesapproximately 5½-in. by 5½-in. by 1-in. Surfaces to be bonded weremachined flat and four pairs of slices were each encapsulated in steelcans as before with the bond material between the slices. The sliceswere oriented in the can to make a sandwich approximately 2-inchesthick. The bonding agents examined were: blended Mo and Ti powders at aratio of 50 atomic percent each, Ti powder (to finish at 0.15 to0.17-in. thick), and Ti foil (0.035-in. thick). One set of slices hadnothing between them. The assemblies were hot isostatically pressed forfour hours at 15,000 psi and 825° C.

After hot isostatic pressing, the assemblies were removed from the steelcans. Five specimens, each at ½-in. by ¼-in. by 1¼-in. were cut fromeach bonded assembly. The bond was at the mid-length location eachspecimen. All of these specimens were evaluated for transverse rupturestrength in the bond area per ASTM B528. Additionally, a set of fivespecimens were produced from a block that had been hot isostaticallypressed at the same conditions. These specimens had no bond and were toprovide a measure of the strength of the Mo—Ti metal matrix composite.Table 3 below shows a summary of the results.

TABLE 3 Mean/ Std. Dev./ Bond Material ksi ksi Mo + Ti powder, 50 116.06.03 a/o Ti Powder 167.5 3.88 None 111.4 13.70 Ti foil 136.0 11.08 Mo—TiMatrix 168.1 6.81 n = 5 for each condition

Example 3 Thin Film Deposition

Magnetron sputtering was used as a means for deposition ofmolybdenum-titanium thin films onto substrates such as glass, siliconwafers and stainless steel.

1. Burn in. The burn in procedure employed was as follows: Power appliedto the target was ramped from 0 W to 100 W, maintained at constant powerfor 10 minutes, ramped to a 1000 W over a period of 50 minutes and thenmaintained constant at 1000 W for 2 hours.

2. Deposition procedure and Parameters. Prior to deposition, thesilicon, stainless steel (AISI 304), soda lime glass, and Corning 1737glass substrates were subjected to chemical cleaning by successiverinsing in ultrasonic baths of acetone and ethyl alcohol. The substrateswere then blown dry in nitrogen and loaded into the deposition chamber.

The chamber was pumped down to pressures lower than 5×10⁻⁶ Torr andfilled with argon to 6.5×10⁻³ Torr for sputter etching of the surface.In this step a negative voltage of 400V pulsing at 100 kHz was appliedto the substrate for 30 minutes, accelerating argon ions to thesubstrate.

After sputter cleaning the substrates, the argon flow was reduced to2×10⁻³ Torr (2 mTorr) and the target was sputter cleaned at 500 W (DC)for 5 minutes.

The deposition on the substrates was performed on the power mode (fixedpower applied to the target) under different conditions where: gaspressure and time were varied. Table 4 lists the parameters employed.

TABLE 4 Parameters for deposition at 1000 W, with substrate at 0 V,grounded. Gas pressure (mTorr) Time 1 2 3 4 5  1 h x x X x X ~2 min x xx

3. Substrate Source Spacing (SSS): SSS was maintained at 5″.

4. Deposition Rate. The deposition rates of Mo—Ti coatings on Si andCorning 1737 glass substrates were determined by the film cross-sectionthickness as measured with SEM.

TABLE 5 Deposition rate (μm/h) for films deposited at 0 V (grounded) Gaspressure (mTorr) Std. 1 2 3 4 5 Avg. dev. Target Mo—Ti on 5.85 6.04 6.436.28 6.55 6.23 0.255 Corning1737 (μm/h) Target Mo—Ti on 5.66 5.64 6.56.5 6.08 0.425 Si (μm/h)

5. Microstructure. With the decrease of deposition pressure, Mo—Ticoatings became denser, as observed by SEM. Coatings on Corning 1737glass substrates were denser than on Si substrates.

6. Adhesion (Tape test). Adhesion of Mo—Ti coatings was measured by tapetest. Mo—Ti coatings on Corning 1737 glass with thickness around 200 nmdemonstrated much better adhesion than those coatings on stainless steeland soda lime glass substrates with thickness around 5 μm, possibly dueto better chemical bonding and smaller total stress.

TABLE 6a Tape test results of Mo—Ti coatings with thickness around 200nm on Corning 1737 glass substrates 1 mTorr 3 mTorr 5 mTorr Target Mo—Ti5B 5B 5B

TABLE 6b Tape test results of Mo—Ti coatings with thickness around 5 μmon stainless steel and soda lime substrates. 1 mTorr 2 mtorr 3 mTorr 4mtorr 5 mTorr Target Mo—Ti 0B 0B 1B 0B 1B on stainless steel TargetMo—Ti 0B 0B 0B 0B OB on soda lime glass

The adhesion tape test performed was based on the following ASTMstandards:

ASTM standard D:3359-02: “Standard Tests Methods for Measuring Adhesionby Tape Test”

ASTM standard B 905-00: “Standard Methods for Assessing the Adhesion ofMetallic and Inorganic Coatings by the Mechanized Tape Test”.

7. Etch rate. Etch rate of Mo—Ti coatings on Si substrates were measuredby immersing the coatings in Ferricyanide solution at 25° C. for 30minutes. Etch rates of Mo—Ti coatings were lower than those of Mo—NbZrand pure Mo coatings.

TABLE 7 Etch rate of molybdenum coatings produced at 1000 W for 1 hour,0 V bias (grounded) in Ferricyanide solution at 25° C. Deposition Etchrate pressure Target Mo—Ti (mTorr) (μm/min) 1 0.063 2 0.064 3 0.098 40.081 5 0.078 average 0.077

8. Resistivity. The sheet resistance of selected molybdenum films wasmeasured using a four-point probe. Results are presented in Table B. Theresistivity of Mo—Ti coatings were higher than those of pure Mo coatingsfor films deposited under the conditions mentioned above.

TABLE 8 Sheet resistance and resistivity values for films depositedunder different deposition conditions Measurements Parameters SheetPressure Power Time Thickness resistance Resistivity (mTorr) (W) (s)(nm) (Ω/) (μΩ · cm) Target 1 1000 117 179 4.45 79.6 Mo—Ti 3 1000 109 1824.50 81.9 5 1000 108 170 4.58 78

With the decrease of deposition pressure, Mo—Ti coatings became denser.Coatings on Corning 1737 glass substrates were denser than on Sisubstrates. Mo—Ti coatings on Corning 1737 glass with thickness around200 nm demonstrated much better adhesion than those coatings onstainless steel and soda lime glass substrates with thickness around 5μm, possibly due to better chemical bonding and smaller total stress.Etch rates of Mo—Ti coatings were much lower than those of pure Mocoatings. The resistivity of Mo—Ti coatings were higher than those ofpure Mo coatings. The uniformity of Mo—Ti is comparable to previous pureMo coatings

Whereas particular embodiments of this invention have been describedabove for purposes of illustration, it will be evident to those skilledin the art that numerous variations of the details of the presentinvention may be made without departing from the invention as defined inthe appended claims.

1-9. (canceled)
 10. A method of preparing a molybdenum-titaniumsputtering target having a single β(Ti,Mo) phase, the method comprisingthe steps of: (a) providing powders of molybdenum and titanium whereinsaid titanium powder is present in an amount of about 5-95 atomic %,based on the total atomic % of the molybdenum and titanium powders, thebalance being molybdenum powder; (b) blending the molybdenum andtitanium powders to produce a blended powder; (c) optionally,consolidating the blended powder; (d) encapsulating the consolidatedpowder; and (e) compacting while heating the encapsulated powder toproduce a MoTi target plate having a single β(MoTi) phase.
 11. Themethod of claim 10, wherein in step (e) the compacting is performed at apressure of 75-300 MPa and the heating is carried out at a temperatureof 900°-1650° C. for a period of 2-16 hours.
 12. The method of claim 10,wherein the molybdenum powder has an average particle size of 0.1-25microns.
 13. The method of claim 10, wherein the titanium powder has anaverage particle size of 5-50 microns.
 14. The method of claim 10,wherein the consolidating of step (c) is performed in a cold isostaticpress.
 15. The method of claim 10, wherein the compacting/heating ofstep (e) is performed in a hot isostatic press.
 16. A method of bondingtwo or more sputter target plates together to produce a large areasputter target, the method comprising: (a) cleaning an edge of each ofthe two or more target plates; (b) optionally, providing a bondingmaterial on an edge of at least one of the two or more target plates tobe bonded; (e) encapsulating the two or more target plates; and (d)compacting while heating the two or more target plates to produce alarge area sputter target plate, wherein the large area sputter targetplate is at least 55 in. by 67 in. in area.
 17. The method of claim 16,wherein each of the two or more target plates has a thickness of ½ inchto 36 inches along the edge to be bonded.
 18. The method of claim 16,wherein each of the two or more target plates has a thickness of 4-8inches along the edge to be bonded.
 19. The method of claim 16, whereinthe target plates are comprised of molybdenum and titanium.
 20. Themethod of claim 16, wherein a bonding material of titanium powder isused.
 21. The method of claim 16, wherein a bonding material of titaniumfoil is used.
 22. The method of claim 16, wherein a bonding material oftitanium-molybdenum powder is used.
 23. The method of claim 16, whereinthe compacting and heating step is hot isostatic pressing and is carriedout at a pressure of 75-300 MPa and a temperature of 700°-950° C. 24.(canceled)
 25. A molybdenum-titanium film produced by sputtering thetarget produced by the method of claim
 10. 26. A molybdenum-titaniumsputtering target having an area of at least 55 inches by 67 inches. 27.A molybdenum-titanium sputtering target having substantially no β(Mo,Ti) alloy phase.
 28. The molybdenum-titanium sputtering target of claim27, wherein the target has a density that is at least 95% of theoreticaldensity.
 29. A molybdenum-titanium sputtering target having a singleβ(Mo, Ti) alloy phase.
 30. The molybdenum-titanium sputtering target ofclaim 29, wherein the target has a density that is at least 95% oftheoretical density.